A curable composition has been used as an optical device-securing composition (e.g., optical device adhesive or optical device sealing material) when producing a sealed optical device.
Examples of the optical device include a light-emitting device (e.g., laser (e.g., semiconductor laser diode (LD)) and light-emitting diode (LED)), a light-receiving device, a hybrid optical device, an optical integrated circuit, and the like. In recent years, an optical device that emits blue light or white light (i.e., an optical device that has a shorter emission peak wavelength) has been developed, and widely used. There is a tendency that the brightness of a light-emitting device having a short emission peak wavelength is significantly increased, and the amount of heat generated by such an optical device further increases.
Along with a recent increase in the brightness of an optical device, a cured product of an optical device-securing composition may deteriorate, and show a decrease in adhesion since the cured product is exposed to higher-energy light or higher-temperature (heat) generated by the optical device for a long time.
Patent Literature 1 to 3 propose an optical device-securing composition that includes a polysilsesquioxane compound as the main component in order to solve the above problem.
However, it may be difficult to obtain a cured product that exhibits sufficient heat resistance and transparency while maintaining sufficient adhesion using the optical device-securing compositions disclosed in Patent Literature 1 to 3 that include a polysilsesquioxane compound as the main component.
Along with a recent increase in the brightness and the lifetime of an optical device, an optical device-securing material used for an optical device has also been desired to exhibit excellent durability with respect to a change in temperature.
Therefore, development of a curable composition that produces a cured product that exhibits excellent transparency, heat resistance, and adhesion, and also exhibits excellent durability with respect to a change in temperature has been desired.